How to connect Generic I2S digital output?

Hi, I’ve connected a Digital Output PCB based on the same chip the Hifiberry Digi+ uses (WM8804). In I2S driver settings in Volumio I’ve selected ‘Generic’ and rebooted. However in Playback > Audio Output I can still only select ALSA. Shouldn’t I be able to select the I2S output here? Did I miss anything?

This is a WW8804 in hardware mode, I assume this should be able to work?